The Rosemont Hyatt, which was hosting Midwest Furfest, was evacuated just before 1 am on December 7 following a chlorine leak, which police are treating as an intentional spill. The leak occurred Saturday night during parties on either the ninth or tenth floor of the hotel, resulting in the evacuation and the hospitalization of nineteen con members. Attendees were permitted to return to their rooms at 3:30 in the morning.